Okay, so now your batteries are flat and need recharging.
I assume you are going to solar or wind turbine recharge these batteries, or
are you intending running an extension lead over the fence and stealing your
neighbour's power to recharge the batteries?

This was drafted out from the thread about solar power installers (my
newsagent sulked). It is to do with battery banking off peak power and
using it during the peak/shoulder periods o run equipment. The batteries
are recharged as off peak equipment.

You didn't go through anything. You have consistently displayed a lack of
understanding of some basic facts. Hint have a look at your last
electricity bill and you will realise where you made your mistake.

As you pointed out, you've omitted the factor of 0.168, reducing the
gross saving to $0.257, and meaning your net saving is negative.

If you're going to do this properly, then you should assume that you're
paying back the loan from the electricity cost savings. You should also
factor in inflation. In practice, as long as both interest rates and
inflation rates are reasonably small, you can subtract the inflation
rate from the interest rate to give a "real interest rate", and then
treat the inflation rate as zero.

The daily saving is 0.168kW * 15 hours * $0.1021/kWh = $0.257 per day.
Treated as 12 equal length months per year, that's $7.83 per month
that's available to pay off the loan.

Run the numbers on that with 6% interest and 3% inflation, and monthly
repayments, and after 10 years, you still owe $289 (in present day dollars).

To break even, you'd need to get the batteries and other equipment for
$791. And this is still assuming that batteries will last for 10 years,
that nothing simply breaks and has to be replaced, and ignoring any
losses in the charge-discharge cycle.

Why? The whole point of the exercise is to increase one's future wealth.
As far as possible you want to factor in all the relevant variables.
Doing otherwise can present the illusion that the path taken is optimum,
when it's not.

Your electricity savings were $0.25 per day, not $1.53 per day, as I
thought you'd realised, because you're drawing 0.168 kW, not 1kW. That
saving is completely wiped out by your own estimation of interest and
depreciation.

The true situation is not so bad, as I indicated, because the interest
drops as you pay back the loan. But there's still a net loss over 10 years.

And the place where you intend to source the 10 year life batteries at
the prices you stated?